* fix(review): restore the prior diff when leaving the Commits view
Clicking a commit in the Commits panel (or its HEAD auto-select) switches
the single session-global diff to commit:<sha>, and switching the panel
back to Tree never switched it back, leaving the review stuck on a
historical commit (shipped as an accepted v1 edge in #994). A page reload
did not escape either, since GET /api/diff serves the current session
diff.
Client-only fix:
- preCommitDiffRef captures the pre-commit diff (full diff type + base)
on the first non-commit to commit switch in handleSelectCommit.
- Leaving Commits for Tree restores it via fetchDiffSwitch; without a
memo (post-reload) it falls back to the session default with the same
resolution handleWorktreeSwitch uses. Exiting while the commit switch
is still in flight also restores, superseding it server-side.
- Any applied non-commit switch clears the memo in fetchDiffSwitch.
- Reload un-trap: a load that is served a commit diff while the opening
panel view is not Commits snaps back to the session default once.
Git status keeps its existing since-base reset; the server keeps its
single-active-diff model unchanged.
* test(review): cover the offered-but-not-first preferred default; document the Commits detour contract
Michael Ramos